Field of the Invention
This invention relates to a process or method for the manufacture of additives, to be included in a concrete mixture, from the natural by-products of sugarcane wherein the final concrete mixture is used in the conventional fashion for construction in a variety of applications.
Description of the Prior Art
The construction industry more and more requires concrete mixtures for a variety of different construction applications. For many years, the use of additives for the purpose of specifically improving the richness and excellence of conditions of concrete in almost any kind of construction has been practiced. Generally speaking, depending upon the specific application for which the end concrete product is intended, the additive is a necessary ingredient which gives the resulting mixture certain desired characteristics or which enhances or combines certain conditions as desired for the specific construction project. Additives, in addition to modifying certain structural characteristics, once they have been added to concrete, modify its characteristics and level of resistance to compression. Typically, such additives accelerate or delay its hardening or curing time as well as providing a fluidizing effect and possibly act as an integral water-proofing material.
Several products are known as concrete additives which once added to concrete modify characteristics such as resistance, plasticity, density, hardening or curing time or quantity of air required to be added, depending upon the specific application for which the end concrete product is intended.
Plasticizing additives also known as fluidizing additives are those devoted to fluidize the mixture. They have a physical-mechanical working behavior since they cover cement particles thus modifying their surface tension and reducing the rubbing or frictional interaction among the cement particles and between cement particles and sand grains also contained in the mixture. On the other hand, plasticizers electrostatically charge cement particles and increase dispersion among them in order to avoid the development of cement cores or lumps. This has the effect of increasing the resistance of concrete to stress.
Concrete resistance or strength depends basically on the cement/water ratio and is inversely proportional to such ratio. In this sense, the more cement added the more resistance to stress in cement and strength of the resulting concrete product. Conversely, the more water added, the less resistance to stress in cement is the result and the less strength or resistance to stress the end concrete product demonstrates. Plasticizing additives fluidize the mixture and thus they reduce the amount of water required to achieve a degree of plasticity and based on the inclusion of less water, such additives also remarkably increase the strength or resistance to stress of the concrete mixture.
The plasticizing additives act as a water reducer which softens the mixture and makes it more workable. It replaces a large quantity of water and so, for a given amount of cement, when a portion of the water is replaced by designated plasticizing additives, the resistance of the concrete increases or in other words a given level of resistance or strength can be achieved while using less cement.
Since the cost of the additive is notably lower than that of the cement portion it replaces, one of the advantages of providing additives is the reduction of costs, apart from a higher internal cohesion and a better cohesion with cooperative structural components used in a building such as a truss.
Another important feature is that the use of additives of the type set forth hereinafter in greater detail allows a lower percentage of added air. The additive of the subject invention and its operational characteristics vary at the beginning and end of the hardening or curing period and modifies the time of water/cement reaction by increasing or reducing it. For example, when fresh concrete is carried on a truck, it is convenient to delay the hardening or curing time in order to increase the life of the mixture thereby allowing it to be transported over long distances. In this case, the use of a retarder would be most convenient.
To the contrary, in the case of prefabricated concrete, it would be convenient to reduce the hardening time in order to increase the rotation of forms thus reducing costs. In this case, the use of an accelerator would be more practical and convenient. If we combine the plasticizing additive with a retarder two main advantages are the result. Such advantages include plasticity meaning cement savings (more resistance to stress with the same quantity of cement) and the retarder increases the life of the concrete mixture prior to hardening.